Corrosion Behavior of Fuel Cladding Material CN-1515 Stainless Steel in Lead-bismuth Eutectic Alloy with Oxygen Control

Domestically-developed CN-1515 stainless steel is one of the candidates for fuel cladding in lead-bismuth-cooled fast reactor due to its favorable irradiation swelling resistance and mechanical properties at evaluated temperature. Because of its severe corrosive effect to metals, compatibility of materials in lead-bismuth eutectic (LBE) alloy should be noticed during reactor development to ensure reactor safety. In this article CN-1515 Austenitic stainless steel was tested at homemade lead-bismuth corrosion experiment device with controlled oxygen concentration between 10^-6% and 10^-7% at 450, 500, 550, 600 ℃ for up to 6 000 h. As a result, protective oxide layer was initially formed at samples tested at lower temperature (≤450 ℃) which loses its protection after extended corrosion period. At higher temperature (≥500 ℃), no oxide layer is formed even with increased oxygen content. Severe nickle dissolution is observed, and dissolution layer depth is positively correlated with experiment temperature and duration.